The present invention relates to generally a machine for winding coils and inserting the same into the slots of a magnetic core of a rotary electric machine and more particularly a machine for winding coils and inserting the same along with wedges into the slots of a magnetic core of a rotary electric machine.
The assembly of magnetic cores such as stators of rotary electric machines includes a step of inserting into the slots of a stator the coils which have been previously wound and a step of inserting the wedges into the slots.
It has been well known in the art that especially when the coils consisting of many turns of a fine conductor are inserted into the stator core of a motor, it is by far preferable to insert both the coils and wedges simultaneously than separately because better performance or qualities of the coils may be maintained; that is, the disconnection of the coil may be minimized; the degradation of the insulation due to the damage to the conductor may be prevented; and the coils may be securely held in the slots by the wedges.
There has been devised and demonstrated a machine capable of simultaneously inserting all the coils and wedges into a stator core. This machine is provided with a plurality of blades which are extended through a stator core and contact the inside peripheral surface thereof so as to guide the coils towards the slots and a plurality of wedge guides which contact with one of the end faces of the stator core so as to guide the wedges towards the slots. The coils to be inserted are previously wound by a separate winding machine and are inserted between the blades according to a predetermined pattern. Thereafter they are inserted into the slots along with the wedges in the manner described above.
However the coil and wedge inserting machine of the type described above has some defects to be described below. When the edgewise wound coil is removed from the bobbin of the winding machine and inserted into the insertion tooling of the coil insertion machine, the coil is disturbed so that when the coil is inserted into the slots, the conductor of the coil is trapped between the stator core and an inserting means and is cut off and the coil cannot be snugly inserted into the slots and securely held by the wedge, thus resulting in the rejection of the finished product. In addition, manual labor is needed to remove the coil from the bobbin and mount it on the insertion tooling. Furthermore, the productivity is low because the connections between the crossover leads are needed after the insertion.
As disclosed for instance in U.S. Pat. No. 2,934,099, there has been invented and used a machine capable of winding a coil and directly inserting it into the slots of a stator core. With this machine, the coils for respective poles are formed individually around bobbins. As a result, the simultaneous insertion of the coils and wedges is impossible. In addition, after the coils and wedges are inserted, the connection between the crossover leads is needed. Furthermore the winding step and the insertion step must be alternately carried out for respective poles. Thus, this machine has a low productivity and a low rate of operation.
As disclosed for instance in U.S. Pat. No. 3,817,295, there has been also invented and used a machine wherein there is provided an inserter tooling consisting of a plurality of blades with different heights and supporting means disposed radially outwardly of the inserter tooling; and a coil is wound around a bobbin formed by two of the blades and one of the supporting means, the wound coil being directly inserted into the slots of a stator core.
The last mentioned machine of the type described above has also a low productivity or a low efficiency because of the following reasons. Firstly, each time a coil for one pole is formed, it must be immediately inserted into the stator. As a result, many insertion steps are needed. In addition, the connection between the crossover leads is still needed. Furthermore since the blades are not uniform in height, the wound coils are increased in length.